Electrochemical Control of Magnetism on the Breathing Kagome Network of Li_xScMo₃O₈

Controlling properties within a given functional inorganic material structure type is often accomplished through tuning the electronic occupation, which is in turn dictated by the elemental composition, that is usually decided at the material preparation. We show here that we can employ electrochemical control of lithium content, with associated electronic occupancy control, to vary the magnetic properties of a material where a kagome-derived network of Mo₃ triangles carry the spin. In this case, Li is electrochemically inserted into LiScMo₃O₈, a layered material containing a breathing Mo kagome network. We demonstrate insertion of up to two additional Li into LiScMo₃O₈, approaching Li₃ScMo₃O₈. Li₂ScMo₃O₈ prepared by electrochemical lithiation is compared to the quantum spin liquid candidate material Li₂ScMo₃O₈ prepared through high-temperature solid-state methods, that has a slightly different structural stacking sequence but a similar kagome-derived network. Magnetic measurements are supported by first-principles calculations, showing that electrons remain localized on the Mo clusters throughout the doping series. As x is varied in Li_xScMo₃O₈, the measurements and calculations reveal the evolution from a diamagnetic band insulator at x = 1 to a geometrically frustrated magnet at x = 2, back to a diamagnetic insulator at x = 3.